Pressure gauge



Feb. 19, 1924. 1,484,068

F. H. HOPKINS PRE S SURE GAUGE Filed Oct. 5. 1921 v DRC s Patented Feb.19, i924.

lastest rece;

FRANK H. HOPKINS. or soMnnvrLLn, MASSACHUSETTS, Assrenon, BY'. lunsNnAS- .s SIGNMENTS, 'ro AMERICAN sCnAnsrnn a sentiranno COnrOnATrON,Ori-BROOK- LYN, NEW rose, ACOnrosArroN or New YORK. l

rnnssunn GAUGE.

Application filed October 3, 1921,'. Serial'No; 504,836.

To all who/mI t may cof/wem.'

Be it known that I, FRANK H. HOPKINS, 'a citizen of the United States,residing at Somerville, in the county of Middlesex and State ofMassachusetts, have invented new and useful improvements in PressureGauges, of which the following is a speci-l fication. Y

The present invention relates to pressureof'which are a curvedfspringtube of flattened cross section generally called lsimply a Springg whichis distorted and flexed by variations in the pressure diierence betweenthe contained fluid and theexternal atmosphere, and a mechanicalmovement'coupled to such tube and adapted to transmit en` larged motionto a hand or other indicator; all contained within a case, usuallyCircular in outline, in which is mounted a dial or record chartcooperative with thek indicator. Such gauges vare produced in a largevariety of classes for measuring different ranges and intensities ofpressure, below as well as above the atmospheric pressure, with singleor double spring tubes. The differences between gauges of these variousclasses, so far as they concern the present invention, consist indifferent sizes of cases and movements, and different lengths anddiameters of spring tubes for the several sizes of' gauge. Besides thesemajor differences, there are minor individual differences between springtubes intended to be exactly alike for gauges of the same class butdiffering from' one another on account of the practical impossibility,either of se- Vcuring exact uniformity in the thickness and elasticquality of the metal walls of the tube, or of flattening or bending thetubes to exactly the same degree.

Customarily the gauge movements are separately made as self-containedunits, each having its own frame, and the cases are separately preparedwithtapped holes to receive the screws` by which the movements aresecured in them; the cases andmove- Y ments being subsequently assembledby per-- class of gauge in special position according to the length ofthe spring to be applied in the gauges of that particular class; and tocompensate for individual variations between springs produced foreachclassv of gauge by providing coupling links of respectively differentlengths'to make Connection between the movement and the spring tube. Ina factory making alarge series of gauges, this has made necessary theprovision of a great number of different cases, andV on the part of theassembling operative has compelled the expenditure of time in selectingcoupling links of special length suitable to' the' special needs of eachindividual gauge. lf theV stock of cases at hand of a particular classshould not be adequate to till an order, cases of another class couldnot be adapted to thepurpose without special preparation', causingincreased expense. Then the time required to select kcoupling links asabove described is a further cause of expense; Since the'part of themovement to `which the coupling link is connected is an arm, rotatableabout an axis, the provision of a longer or shorter link to accommodate'amadeto Compensatefor minor variations in thel lengthof spring tubesofthe same class, the means employed for that purpose have permitted' ofonly the most limited range of adjustment. Such adjustment as waseffected wasv made at the-expense of accuracy. Y j Y The usual locationof the screws forattaching the movement .to-the case has heretofore beenat the'ends .of the frame near the posts which connect the top andbottom plates of the frame. It frequentlyhappens that .either that plateof the frame movement' which lies against the back wall of theV case, orthe abutting surface of the case itself, is not in a true plane, andwhen that occurs such distortion is frequentlyV given to the trame insecuring it to the case that the staff carrying Vthe indicator does notturn `freely inlits bearings, but sticks and so causes inaccuracy` byresisting the resilient distortion of the spring tube Aand, laggingbehind the pressure change being indicated. The customary method ofmount- -ing` the movement in the case is to pass theV screws throughholes provided for themV Yin the bottom plate of the movement frame intothe tappedv holes in the case, which is anroperation of some delicacyand liable to be of uncertain time because ot the liability or' thescrews to fall out of place before their of.v the spring tubefisattached, although inV general the movement is applied directly to theback wall of' the case. All that has been said heretoforeapplies equallyto the suspended movement type as well as to the other.

The objects of this invention are first to lenable the movements andcases of each size to be assembled with one another and with springtubes varying greatly in length to produce gauges ofV different classes,without requiring special vpreparation of the case for eachseparate'class, and with coupling links of the same length in all gaugesof the saine size; second, to permit a wide range of angularadjustment'of the movement in the case and to compel such adjustment totake place about the axis on which the indicator turns; third, to avoidand overcome the conditions which have heretofore caused the indicatorcarrying stali" to bind or stick in the movement frame; and fourth tofacilitate the assembling and mounting ofthe movement in the case. Themanner in which these objects are accomplishedV and the principles'andmeans in which the in'- vention essentially consists. are explained inthe liollowing specification with reference tothe drawings. f

ink the drawings,- Y

- Figure 1 is a face Vview of a gauge with the crystal Yand'dialremoved` to show the operatingparts in which the new features of theinvention particularly reside.

Figure 2 is a similar view of a. specifically different class of gauge',in which the same case and the same movement as shown in Figure l areemployedin a diiierent relation to one another.

Figure 3 is a detail .view showing the rameotthe movement in two ofitspossible` positions.V i

Figure 4 is a similar view of the movement traine showing two otherpossible po,- sitions. "1 i Figure 5:` is an elevation of thev entiremovement v in connection with4 the back wall of the case, which is shownin section.

Figures 6 and 7 are views similar in principle to Figures 3 and eillustrating modifications of the invention.

Lilie reference characters designate the Vsame parte inl all the lgures.

a represents the casev ofthe gauge, V.o

the curved spring tube oiv the familiar Y' Bourdon type, and c thesoclret to 'which the entrance end of the spring tube'is made fast andfrom which extends an external tion to a hand for equivalent indicator.k

The particular movement here shown is in principle, and except for thefeatures novel 4with this invention and later described, a common andfamiliar one having a frame composed of a bottom plate l, a topvplate 2and posts 3 and 4C; a gear segment 5,011 the staiil 6 andgapinion 7,attached to the staff 8 which carries the indicator, and in mesh withthe gear segment. A hairspring 9 is fastened to the staii ,8 and to thepost 3,. and' a slotted bar 10 embracing the stai 6 and fastened to thesegment 5 by a screw 1l provides an adjustable arm to which the couplingmember l2 connecting the movement with the spring tube may be attached.

In Figure l, which shows a single spring gauge, the coupling member l2is a link pivoted at its opposite ends tothe spring tube and to the bar10, respectively, while in Figure 2, which shows a dor-.ble springgauge, the equivalent coupling member 12a is pivoted to a rocker l?)which is iulciumed at le to one or" the spring tubes b1 and is connectedby a linlr l5 to the other of the tubes, o?. Holes 16 (Figure and l?(Figurel l) are provided in the segment a opposite sides'of the stati 6for reception of the screw ll, whereby it is possible to place the barwith that end which is pivoted to the coupling at either side oi Ythestaff 6 and at various distances from such stad. It will be noted Vbycomparing Figures l and E?, that the position oit theV movementV isrelatively diiiferent in these two classes oi gauge, and it will beappreciated that with .still other classes cie-gauge having,respectively, longer or, shorter spring tubes, either double or single,the'movement may be required to assume still vother positions, and

also larger or smaller movements may loeV needed. By this invention lhave it Y possible to accommodate the sanie movement ln that form of theinvention shownzin VFigures 1 to inclusivdthe bottom plate 1 isprovidedv with two slots 18 :and 19, both concentric with the stad. 8and of the same radius, the plate being made with sufficient widthsurrounding the stai to accommodate these slots. `Screws-20 and 21mounted in the back wall al of the case and passing through the'slots-18 and 19, respectively, permit'the movement to be adjusted around thisaxis. Their heads overlap the rims of the slots whereby the movement ismade fast j when the screws are driven tight. Preferably the screws areat diametrically opposite sides of the` staff, and the slots areenlarged lat pointsV diametrically opposite toy one another sunicientlyto enable the screw heads to pass through such enlarged parts.Preferably, also, the enlargements are at one end `of each slot,although they may be provided in other locations if desired.

'In order to position the staff at an exact point in the'case andmaintain it in the same position, however the whole movement may beadjusted, a swivel. or pivot connection is made between the movement andthe back wall. Most conveniently such `engagement is provided by anextension of the bushing 22, in which the stati:1 8 has its bearing inthe bottom plate 1, below or to the rear o said plate, and by a socketor recessa2 of complemental diameter i-n the back wall a1.` `Otherspeciiic forms of swivel may, however, be made equivalent to that heredescribed and such are included` within -mv claims to vprotection forthis vfeature of the invention. The one described .is preferred toothers on account of its Vsimplicity and low cost.V VThis swivelconnection provides a positioning means additional to thel screws and isadequate together with one only of the screws, to securethe movement inplace, but two screws are preferred on account of their greatersecurity.

lWith the attaching screws arranged as in Figure 3, with the screw 20occupying the slot 18 and screw 21 occupying slot 19, .the

movement may be adjusted in the sectorV where the arrow 'h is appliedbetween Ythe full line and dotted line positions of the movement platel, so as to `accommodate single springsjorn .any length between thatshown at b in full lines and that shown in dotted lines at bi Then -byremoving the movement and reengaging it, with the screw 2O passedthrough the slot 1-9 and the screw 21V through theslot 18, the movementmay be adjusted in thehsector denoted by the arrow z' to accommodatedouble'spring gauges linnwhich the length of the spring tubes may varyfrom that shown in full lines at ,b2 to` thatshown in dottedlines atb4.4 Furthermore, l contemplate provid- 'ing'.y alternative holes 23 and24 on opposite sides of the staE 8, andequally spaced bey these. Anycase of a given size may beas-V semb-led with a move'ment'of a suitablesize anda spring tube of any length without special preparation. No timeneed be lost, prior to assembling, in forming special screw holes toyaccommodate the 'movement to a particular length of spring or inyselecting a case specially prepared for a givenclass of gauge to receivethe movement and spring of that class, or in selecting a coupling link12 or 12a of special length to compensate for inevitable variations indifferent gauges between the distance of the end of the spring from themovement. Instead, the assembling operative may take the cases andmovements as they come, set the clamping screws 20 and 21 loosely in thecase before mountingthe movement7 lay thek movement in` place by passingthe enlargements; of the slots 18 and 19 over the heads of the screws,connect a link of standard length tothe spring tube and the arm 10,meanwhile turning the movement until itis brought to the properadjustment to receive the pivot screw, and finally tighten the clampinrscrews. .Thus the assemblngmay be carried voutin theminimum time,whichis a substantial item ofsavmg 1n Va large vi'actory.

The enlargements of the slots to admit the ion screw heads contribute tothis time saving, Y

i'ortheir presence avoids the annoyanceV and yimpediment to theplacement of the screws Vcaused by the hairspring when the screws areinserted through the slots into/the receiving holes. Y. They can beplaced much' more quickly and surely when they are loosely placed intheir holes before thev movement is applied.. Still .more, theseenlargements aid inthe Vremoval of a defective movement and thesubstitution of a new oneinf an alreadyinstalled gauge. i

,. In addition to the saving inthe cost'oic manufacture, the inventionresults in'uniformity in the angularity of the connecting link to thesegmentl arm in all gauges/where the size of movement and the radius ofcurlvature of the spring tube are alike, thus giving uniform accuracy,so far as angularity ofk the connecting link niiuences acit@ f vso Ybottom plate 1b as the center about which this adjustment takes place isfixed, it does notv alter the relation of the indicator to the dial,which is mounted independently of the movement frame on the case. As theattaching screws are, in any adjustment, relatively far re- Vmoved fromthe line connecting theposts 3 and 4 or the movement instead of beingsub-'- stantially in that line and close to .the posts,

danger of so warping the iframe as to cause the movement to stick islargely avoided. If

the bottom plate andthe gauge wall should not match truly, whateverdistortion would be given to the vmovement by tightening the screwswould take place locally in the lateral enlargements of the bottom plateand would not cause the center statie to stick.

The same principles and advantages hereinbefore explained apply togauges of the suspended movement type as well as to those in which the,movement is applied and secured directly to the rear wall of the case.As to such suspended movement gauges, the web on which the movement ismounted is equivalent to the back wall of the case and is includedwithin the meaning ot the term back wall or terms of similar import usedin the appended claims.

A modification is shown in Figure 6, the purpose and eiect ot which isto obtain a wider range ot angular adjustment without changing the`relation of the separate attaching screws and slots. rlfhe bottom platela is here made with a relatively larger circular part and is providedwith slots 18a and 19a which are of respectively different radii and ofsuch length that their ends overlap. rlhus without changing the screws,the movement may be adjusted through more that one half a revolution.But by shifting the screws into other holes 25 andr26 the adjustment maybe carried on to a full revolution.

Iny another form shown in Figure 7 the is entirely circular and itsradius is greater thanthe distance ot' either the post 4 or the stad 6from the center stati' 8. Screws in any desired number are setto overlapthe rim or lip ot the plate.V Evidently here the adjustment maybecontinued without vinterference and without need of shifting the screws`throughout an entire revolution. lt may be noted that in any case,whether the'screws pass through slots or merely overlap the rim of the.plate, the plate has a lip or lips which will overlap and engage'withthe heads of the clamping Screws.

W'ha-t I claim'and desire to secure by Letters Patent is: .n l. Apressure gauge comprising, in combination with a case andV a Bourdonvtube mounted operatively in said case, ka self*- contained indicating umovement including a frame, ari-indicator stad rotatably mounted Yineaoee in said frame and motion transmitting means fromy said staffadapted to be connected with said Bourdon tube, said movement as a wholebeing mounted inthe case with provision for angular movement about theyaxis of sads'tai. i

' 2. The pressure rgauge combination as set forth in claim 1 andinwhich'the saidy movement frame is provided with a curved lip concentricwith said axis, and a clamp member is mounted on thek case and lconstructed and arranged to overlap and clamp said lip. i Y

3. A pressure gauge as set forth in claim Y 1 in'which the movementframe includes a bottom `frame plate having a lip concentric with saidaxis and the case has a back'wall against which said frame plate lies;lthe plate and back wall having complemental pivot and sockety elementsin the line of said axis, about which the rotary adjustment of themovement takes place, combined with a clamp device fixed to the backwall and overlapping said lip.

4. ln a gauge a case having a back wall with one member of a swivelcouplingya clamp mounted on said Wall ata given distance from saidmember adapted to grip and hold the after-named movement plate, and anindex-operating movement having a swivel member complemental to thatofsaid wall adapted to be coupled therewith and includ'- ing a platehaving a lip concentric with said swivel coupling, arranged to beoverlapped and engaged by Vsaid clamp, whereby the movement may beadjusted angularly about the swivel coupling and made fast in variouspositions of adjustment to accommodate spring tubes of various lengths.

5. A pressure gauge comprising-a case, a Bourdon tube and an indicatoroperating oef movement consisting-of arframe, an indicator staff, andmeans adapted to be coupledto said Bourdon tube and arranged to trans- Y`mit movement therefrom to said statt', vcombined with means formounting said movement with provision for adjustment angu- Vlarly abouta given center to accommodate Bourdon tubes ot different lengths in thevsame case. i

6; A pressure gauge comprising'acase, a

movement including a frame and 1a center Y staii", and a swivelconnection .between the case and movement consisting of a projectionextendingfrom the latter in alinement with the centerl statt', and asocket or recess reol in a wall of thecasewherein said projection withsaid sta through which said attachff ing screw passes and in which thereis an enlargement adapted to pass over the head of said screw7 the slotbeing elsewhere of less width than the greatest Width of said screwhead.

8. A pressure gauge comprising a circular case having in its rear Wall acentrally located socket or recess, a curved spring tube operativelymounted in said case, a movement including a bottom frame plate,complemental frame members and an indicator carrying steif, a bearingsleeve for said staff mounted in the bottom plate and projecting thenceinto the said socket in which it fits in the manner of a pivot, saidbottom plate having alip concentric with the stall", and a clamp mountedon the gaugey Wall arranged to overlap said lip for securing themovement in various positions of angular adjustment about the axis ofthe staff.

In testimony whereof l have alixed my signature. v

FRANK n. HoPKiNs.

